Re: [Regression] rt2800usb - Wifi performance issues and connection drops

From: Alexander Wetzel <alexander@wetzel-home.de>
To: Thomas Mann <rauchwolke@gmx.net>
Cc: Linux regressions mailing list <regressions@lists.linux.dev>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Stanislaw Gruszka <stf_xl@wp.pl>,
	Helmut Schaa <helmut.schaa@googlemail.com>,
	Johannes Berg <johannes.berg@intel.com>
Subject: Re: [Regression] rt2800usb - Wifi performance issues and connection drops
Date: Wed, 8 Mar 2023 13:10:13 +0100	[thread overview]
Message-ID: <97ad368e-7379-37db-8103-3b4ecc2342fd@wetzel-home.de> (raw)
In-Reply-To: <20230308112650.3c72d6f2@polar.lan>

>>>> @Thomas:
>>>> I've also uploaded you my binary kernel I'm running at the moment
>>>> here: https://www.awhome.eu/s/5FjqMS73rtCtSBM
>>>>
>>>> That kernel should also be able to boot and operate your system.
>>>> Can you try that and tell me, if that makes any difference?
>>
>>   >
>>   > i can't boot the binary kernel here, as the initramfs is included
>>   > in my kernel, if you send me a patch, i can apply it and test it.
>>
>> That was an unpatched kernel. Idea was to verify that it's not a
>> compiler issue. (You seem to be using a hardened Gentoo profile.)
>>
>> Can you share your initrd, so I can include it? (Mail it to me
>> directly, upload it to bug in buguilla or send a link to some cloud
>> storage.)
>>
> I can't share this config, as it's a production system, and i'm not
> allowed to run abitrary binary code on the system. As 6.1.x works
> without a problem, i don't think it's a compiler problem. I will try to
> get a none hardened compiler and recompile the kernel.
> 

I was suspecting something like that. I may try the same in reverse. But 
it's so far quite some way down on the list. There are more promising 
ways to spend the debug time I have for so far.

But one remark:
As far as TX is concerned 6.1 and 6.2 kernels are handling TX in 
drastically different ways for many - including yours - cards.

The patch you identified as culprit is well after the move to the new TX 
mode of operation and only fixes a comparable minor issue.

Your setup seems to require both, the move to iTXQ AND this minor fix.

>>
>>>>
>>>> I'm also planning to provide some more debug patches, to figuring
>>>> out which part of commit 4444bc2116ae ("wifi: mac80211: Proper
>>>> mark iTXQs for resumption") fixes the issue for you. Assuming my
>>>> understanding above is correct the patch should not really
>>>> fix/break anything for you...With the findings above I would have
>>>> expected your git bisec to identify commit a790cc3a4fad ("wifi:
>>>> mac80211: add wake_tx_queue callback to drivers") as the first
>>>> broken commit...
>>>>
>>>> Alexander
>>>
>>
> 